The WBIS is a 11-item instrument for measuring the extent to which overweight individuals think of themselves in terms of prevalent negative stereotypes about overweight and overweight individuals. Respondents can express their level of agreement on a 7-point Likert scale ranging from 'strongly disagree' (1) to 'strongly agree' (7). Items 1 and 9 need to be scored reversely.

scoring_wbis(
  data,
  items = 1:11,
  keep = TRUE,
  nvalid = 9,
  digits = NULL,
  reverse = c(1, 9)
)

Arguments

data

a data.frame containing the WBIS items orderd from 1 to 11

items

A character vector with the WBIS item names ordered from 1 to 11, or a numeric vector indicating the column numbers of the WBIS items in data.

keep

Logical, whether to keep the single items and whether to return variables containing the number of non-missing items on each scale for each respondent. The default is TRUE.

nvalid

A numeric value indicating the number of non-missing items required for score calculations. The default is 9.

digits

Integer of length one: value to round to. No rounding by default.

reverse

items to be scored reversely. These items can be specified either by name or by index. Default: 1, 9

Value

The function returns 2 variables:

  • nvalid.wbis: Number of valid values (MAX=11)

  • score.wbis: WBIS Score

Details

  • Number of items: 11

  • Item range: 1 to 7

  • Reverse items: 1, 9

  • Score range: 11 to 77

  • Cut-off-values: none

  • Minimal clinically important difference: none

  • If more than 2 items have not been answered, then the total mean score is not calculated.

References

Durso, Latner (2008) (https://doi.org/10.1038/oby.2008.448)

Hilbert et al. (2014) (https://doi.org/10.1371/journal.pone.0086303)

Examples

if (FALSE) { library(dplyr) items.wbis <- paste0("WBIS_", seq(1, 11, 1)) scoring_wbis(mydata, items = items.wbis, reverse = c(1, 9)) }